James Bowling

NSX Controller Troubleshooting - Logical Switching

1 minute read

So to add to my last post on troubleshooting VXLAN through esxcli, I will now move into troubleshooting and gathering information from the NSX Controller instances. In this post I will show you some commands that are extremely useful from the NSX Controller when trying to troubleshoot logical switching in NSX. Again, a lot of this was shown to me by @trainingrev during NSX training but wanted to document and share…

Ready…set…GO!

So troubleshooting logical switching in NSX will typically utilize the commands below or at least it is a good starting point IMO:

Check to make sure that there is connectivity.

To check this, ssh into the NSX controller and run the following command: show control-cluster connections

On every ESXi host there is a daemon running called netcpa. This is the NSX controller. You can view the logs of the controller to see if there are any connectivity issues with ESXi by doing: show log cloudnet/cloudnet_java-vnet-controller.log

Next you may want to check the status of the controller. You can check the status by running: show control-cluster status

Now check to see what roles are associated with it. This can be achieved by running: show control-cluster roles

You can also check to see which controller is responsible for a particular VNI. Remember that NSX uses a method called “slicing” to split control of a VNI across the distributed controllers. You can see who has a particular VNI by running: show control-cluster logical-switches vni

Now last, but definitely not least, you can view the various table entries for VTEP, MAC, and ARP. Here are the commands:

VTEP - show control-cluster logical-switches vtep-table

MAC - show control-cluster logical-switches mac-table <VNI>

ARP - show control-cluster logical-switches arp-table

So as I go through my NSX journey and come across these great tidbits of information I hope you find them as useful as I have. Please feel free to comment below or ask any questions. If I can’t answer it then I can at least help point you in the right direction or to the right resource. Thanks for dropping by and look forward to more posts on tips and tricks to troubleshooting NSX.